Calking and sealing composition containing block copolymers



United States Patent 3,325,430 (TALKING AND SEALING COMPOSITION CON- TAINING BLOCK COPOLYMERS Michael H. Grasley, Walnut Creek, Califl, assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 22, 1965, Ser. No. 502,395 Claims. (Cl. 260) This invention concerns new compositions of matter particularly superior for sealing cracks, crevices, joints and leaks to make them water-proof. More particularly, it pertains to special compositions containing block copolymers as an elastomeric component, the compositions being characterized by their adhesiveness, flexibility and elastomeric properties.

Compositions for sealing cracks and other openings such as joints and the like are commonly prepared by compounding a drying oil such as linseed oil with a filler such as clay or tale to form a putty which can be pressed or forced into cracks and the like by ordinary hand pressure or from a calking gun.

With the advent, especially, of curtain wall construction techniques, the deficiencies of the well-known putties of the past were especially pointed up, since these traditional compounds did not fulfill the new requirements of tensile strength, elongation, elastic recovery, adhesion and long term dependability. As a result, modern sealants have been developed which are usually high solids elastomeric adhesives. Many of the common elastomers have been used as sealant vehicles which may be divided into two types, namely, those that develop elastomeric properties by .curing through solvent evaporation and, secondly, those that develop elastomeric properties through a chemical reaction such as cross-linking or polymerization. While chemically curing sealants of the recent past have usually had the best performance, they are also the most expensive. The solvent type of sealants which have been recently developed may be inexpensive, but they are generally lacking in certain areas of performance.

It is an object of the present invention to provide improved solvent-type sealants. It is a particular object of the present invention to provide an improved elastomeric solvent-type sealant especially designed for the calking and sealing of joints and the like. Other objects will become apparent during the following detailed description of the invention.

Now, in accordance with the present invention, improved compositions are provided wherein the elastomeric component thereof is a block copolymer of the group consisting of polymers having the general configuration TABLE I Component: Parts by weight (A) Block copolymer 100 (B) Mineral oil extender 0-50 (C) Volatile hydrocarbon vehicle 75-200 (D) Resin of the group consisting of hydrogenated rosin, terpene resins, polymerized rosins, pentaerythritol esters of rosin, polyalkenes and mixtures thereof 50175 3,325,431 Patented June 13, 196

(E) Alkylated dimethylol phenol-formaldehyde resin M l55 (F) Coarse filler as defined hereinafter 15040 (G) Fine filler as defined hereinafter 10-30 Each of these components has been found to be essen tial in promoting the optimum combination of propertie which is required of a satisfactory sealant. These prop erties may be summarized as follows:

TABLE II Criteria for a single component elaslomer sealant (I) In use:

( 1) Rheology should allow easy transfer from con tainers.

(2) Rheology should be designed for application Non-sag for vertical joints. Self-leveling for horizontal joints.

(3) Extrusion properties must be satisfactory at 211.

working temperatures.

(4) Tooling-Easily tooled to desired surface finish and level.

(5) Product should not be toxic or have undesirable odor.

(6) Product should be easily cleaned from tools and surfaces.

(II) Performance:

(1) Excellent adhesion to building surfaces.

(2) Develop good elastomeric properties.

(3) Should reach a tack-free state rapidly.

(4) Exhibit slight shrinkage.

(5) Adequate cohesive strength for applicationnever more than adhesive strength.

(6) No color change.

(7) No adverse effect over ambient temperature range.

(8) Not affected by sunlight, water, oxygen, ozone,

wind pressure, dirt.

(9) Good chemical resistance.

(10) Non-staining and non-corrosive.

(l1) Maintain desirable properties over estimated life. i

(12) Performance should comply with applicable specifications.

The block copolymers forming the important elastomeric component of the present composition have the general configuration If the copolyrner is not hydrogenated, the blocks A com prise poly(vinyl arene) blocks while the block B is a poly(conjugated diene) block. The blocks A normally have average molecular weights as determined by osmotic molecular weight methods as they are related to intrinsic viscosity of between about 8,000 and 45,000, while the conjugated diene polymer block has average molecular weights between about 35,000 and 150,000. If the copolymers are hydrogenated the molecular weight ranges remain in roughly the same ranges. Two preferred species of such block copolymers include those having the block configuration polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene as well as their hydrogenated counterparts. The hydrogenated counterpart of the second of the above defined block copolymers is of especial interest, not only because: of its high stability but because of the elastomeric nature of the hydrogenated mid-section which resembles that of an ethylene-propylene rubber while the end blocks either remain as polyvinyl arene blocks or if hydrogenated become saturated blocks typified by cyclohexane polymer blocks. Thus, the fully hydrogenated preferred species has the block configuration polycyclohexane-[ethylene-propylene copolymer]-polycyclohexane.

These particular block copolymers have the unique feae of attaining the stress-strain properties of an elastor without the requirement that it be subjected to curing vulcanization. Thus, they are sharply differentiated rn other rubbers such as natural rubber, polybutadiene,

R and the like which require vulcanization in order to tin satisfactory stress-strain properties. Consequently,

sealant compositions of the present invention repret a hybrid between the two general types of elastomeric king compounds heretofore developed in that it cures solvent evaporation but does not require vulcanizan or chemical cross-linking such as is necessary with polyurethanes and the like.

The compositions of the invention may function satistorily without any mineral oil extender but it has an found that the oil functions in an unexpected man- 7 not only to plasticize, soften and tackify the comsition but also creates a consistency especially suitable rapid escape of the volatile solvent utilized for viscosipurposes. On the other hand, the proportion of oil which 1y be incorporated is strictly limited, since if proportions excess of 50 phr. (parts by weight per hundred parts weight of block copolymer), then poor adhesion to surfaces being sealed results.

The type of mineral oil utilized for this purpose is not pecially critical but should be one which does not volatie under the conditions of service. Consequently, it is eferred that it have a boiling point above about 550 F.

.d a viscosity between about 40 and 250 SSU at 210 F.

[Ch oils are often referred to as processing and rubber tending oils and have aromatic contents varying from out 10% to about 50%.

One of the important components of the composition ay be regarded as a temporary component in that it a relatively volatile liquid hydrocarbon of such a char- :ter that the other components may be thinned thereby it from which it will readily escape over a period of mm several weeks after application of the sealant into a service position. Consequently, it is necessary that the quid hydrocarbon boil between about 100 C. and 175 Such hydrocarbons are especially typified by toluene, lene and mixtures of hydrocarbons boiling within this :neral range, often referred to an mineral spirits. If 1e boiling range is below the minimum specified, the )lvent is released too rapidly and surface hardening of re remaining components may occur before the sealant is roperly leveled into position. On the other hand, if the oiling range is extended beyond that specified then it is slow to release properly and the composition may be ibject to flow or sagging, especially when it is placed in a ertical position.

One of the major components of the composition under onsideration comprises a resin. It would, of course, be onvenient to utilize only a single resin in such composions but this has not been possible when employing the ubject class of block copolymers. Ideally, a resin may be arded as a physical softener which acts as an interiolecular lubricant for the elastomercomponent and erforms a number of important functions including inreasing plasticity, tack, workability and the wetting of igments and fillers. However, it is immediately apparent any formulator confronted with a bewildering array 'f proprietary resinous products that these may not be lsed indiscriminately. The choice is sharply narrowed by equirements for polarity, particular molecular structure, .hemical reactivity and molecular weight, all as they are elated to the elastomeric component. Moreover, the nolecular weight must be chosen to provide suitable iscosity, tensile and tear strength as well as melting Joint.

It was found that ordinary phenol-formaldehyde resins were not compatible with the block copolymers. Polynerized petroleum hydrocarbons were also unsatisfactory aut terpene polymers were found to be adequate as were polymerized rosin and hydrogenated rosin together with pentaerythritol esters of rosin and polyalkenes. The most desirable class of materials comprised the hydrogenated rosins (either gum rosin or wood rosin) which unexpectedly result in dramatically increased elongation of the compositions under consideration. Furthermore, of course, the saturated nature of the hydrogenated rosins make them highly resistant to oxidation, discoloration and changes in solubility characteristics when exposed to air and sunlight.

While all of these factors are satisfied by the particular class of resinous materials described immediately above, it was found in the course of developing the compositions of this invention that if these resins were the sole resinous component the compositions were lacking in one essential respect, namely, in adhesion to the surfaces being sealed. Sealant adhesion to such surfaces is a stringent requirement and usually the most difiicult to meet. It has been noted hereinbefore that the oil content is critical in this respect and was therefore restricted to the recited range of ()-SO phr. Even when so restricted, however, the resulting compositions containing only the one resin of the class given hereinbefore did not exhibit proper adhesion.

Consequently, some enhancement of adhesion was required by a further modification of the composition. This was found in the use of a critically limited amount of alkylated dimethylol phenol-formaldehyde resins. The use of this class of oil-soluble resins was investigated over much wider concentration ranges. However, it was noted that when proportions larger than those specified (1550 phr.) were employed the resulting compositions including the block copolymer exhibited poor physical properties indicative of incompatibility. However, when utilized within the restricted range specified there was a dramatic increase in sealant adhesion to all types of surfaces investigated. The alkylated dimethylol phenol-formaldehyde resins have the general configuration as follows:

OH OH OH H O CH: CH CH C Hz OH I l l R R n R In the above general formula (which is not to be considered limiting but illustrative), the groups R represents alkyl radicals having from 4 to 9 carbon atoms each. These impart the oil solubility required for compatibility in the present system. The average molecular weight of the resins lies between about 350 and 1,500 while the methylol content is preferably between about 5 and 20% by weight. While the methylol groups are normally regarded as being situated on the terminal phenolic groups, the methylol content may be increased without molecular weight increase by replacement of one of more of the R alkyl radicals with methylol radicals. Alternatively, methylol radicals may supplement the alkyl radicals instead of replacing them. In the usual commercially availabe dimethylol resins of this class, the alkyl radicals are believed to be in positions para to the hydroxyl groups of each phenol radical. The preferred resins of this class have softening points (Nagel) of 95 C., specific gravities at 25 C. of between about 1.02 and 1.04 and acid numbers about 30 and 40.

In order to be effective commercially, and competitive with other similar products, it is essential that the entire composition be relatively low in cost, while still maintaining satisfactory physical properties for the sealing requirements as detailed hereinbefore. This may be achieved primarily by the use of fillers, but here again the choice, which immediately may appear to be extremely large, turns out to be relatively limited. Moreover, it was discovered that no one filler satisfied all the requirements of the compositions containing the subject block copolyme-rs 5 but, in fact, two fillers were found to be essential. It was found possible to employ limited amounts in the order of 150-400 parts by weight based on one hundred parts by weight of the block copolymer of fillers comprising alkaline earth metal carbonates, oxides and clays having relatively coarse particle diameters between 5 and 75 microns. However, if larger proportions were employed, then the physical properties of the resulting compositions degenerated, particularly insofar as elasticity and cohesive strength were concerned. Therefore, it was necessary to utilize in combination with the relatively coarse filler other fillers having extremely finely divided particles in the order of 0.005 and 1 micron. Depending on the particular filler employed and its particle size, this finely divided filler should be present in amounts between about and 300 phr. and may comprise silicas, particularly fumed silicas, metallic oxides and alkaline earth metal carbonates. The fumed silicas being of such fine particle size (in the order of 0005-002) are used only in small proportions up to about 30 phr. However, for the somewhat larger but still small sized alkaline earth metal carbonates and oxides wherein the particle size vary from about 0.025 to 1 micron proportions in the order of 150 and 275 phr., may be employed. However, if attempts are made to entirely replace the relatively coarse fillers having a diameter of 5-75 microns with the finer fillers, it is unexpectedly found that the percent of shrinkage of the entire composition rises sharply and results in unsatisfactory service.

Summarizing the above compositions, the following table gives both the broad range of permissable proportions of each of the essential components and also in a separate column the preferred range of proportions thereof.

TABLE III Parts ByWeight Component Broad Range Preferred Range (A) Block copolymenm 100 100 (B) Extending oil... 0-50 20-35 (C) Volatile hydrocarbon. 75-200 85-125 (D) Rosin-type resin 50-175 110-155 (E) Dimethylol phenolic resin -50 520-40 (F) Coarse filler 150-400 175-225 (G) Fine filler 10-300 150-275 In addition to the essential components discussed in detail above, other optional materials may be employed for improvement, modification or stabilization of these compositions. For example, antiozonants and antioxidants may be utilized. A preferred class of antioxidants comprise the nickel dialkyldithiocarbamates. Specific compounds in this group include nickel dibutyldithiocarbamate, nickel diamyldithiocarbamate and nickel diisooctyldithioc-arbamate. These may be supplemented by the presence of alkylated phenols and their derivatives as well as by aromatic amines. Phenolic antioxidants are especially desirable, of which one of the most effective is the class of trialkyl-substituted tri(alkyl hydroxybenzyl) benzenes. Specifically, an especially desirable antioxidant within this group is 1,3,5- trimethyl 2,4,6-tri(3,S-di-tertiarybutyl-4-hydroxybenzyl) benzene. These antioxidants and antiozonants are to be used in the usual additive amounts, namely, between about 0.25% and about 1% each. Coloring materials and masking agents may be utilized such as carbon blacks, titania etc., as long as they do not interfere with the effective set of physical properties obtained by the special combination of components discussed above.

The physical testing of the subject sealants presents a problem since they are in effect a hybrid between the solvent release type of sealant and the curative sealants. Consequently, the tests such as those detailed by the American Standards Test A116.1-1960 apply only when they are modified to take this hybrid character into account. The most realistic type of testing is field testii wherein the sealants are placed in a working position suc as in the sealing of curtain wall sections and observed f( a period of time. The following compositions have bee tested under such circumstances.

Sealing of this curtain wall building was effected b1 filling the joints between the concrete slabs, the joint being about /2 inch deep and varying from A; to inches in width and 12 feet high. The sealant had gooi working and handling properties and did not shov evidence of sagging. Periodic inspection after installatior showed that the sealant had cured well, i.e., the solven had evaporated satisfactorily and no shrinkage problem: were evident. There was no sign of adhesion failure anc all indications implied that the subject building sealan' compositions were superior to other solvent-type sealant: and unlike most of the latter can be used successfully it moving joint applications in place of the more expensive chemically curing sealants.

I claim as my invention:

1. A calking composition for sealing crevices, cracks leaks, joints and the like to make them waterproof com prising an intimate mixture of:

Parts by weigh (a) a block copolymer of the group consisting of polymers having the general configuration A-B-A wherein each A is a poly(vinyl arene) block having an average molecular weight between 8,000 and 45,000, and B is a po1y(conjugated diene) block having an average molecular weight between 35,000 and 150,-

000, and hydrogenated derivatives thereof (b) a mineral oil having a boiling point above about 550 F. and a viscosity of 40 to 250 SSU at 210 F. (c) a liquid hydrocarbon boiling between about C. and 175 C. (d) a resin of the group consisting of hydrogenated rosin, terpene resins, polymerized rosin, pentaerythritol esters of rosin, polyalkenes and mixtures thereof (e) an alkylated dimethylol phenol-formaldehyde resin having an average molecular weight between 350 and 1,500, a methylol content between 5% and 20% and alkyl substituents of 4-9 carbon atoms each (f) a filler of the group consisting of alkaline earth metal carbonates, oxides and clays having average particle diameters between about 5 and 75 microns (g) and a filler of the group consisting of silicas, alkaline earth metal oxides and carbonates having average particle diameters between about 0.005 and 1 micron 10-300 2. A composition according to claim 1 wherein (a) the block copolymer has the configuration polystyrene-polybutadiene-polystyrene. 3. A composition according to claim 1 wherein the filler (g) is an alkaline earth metal carbonate having an =1'age particle diameter between about 0.025 and 1 min and is present in an amount between about 150 and 1 parts by weight.

I a block copolymer having the configuration )olystyrene-polybutadiene-polystyrene wheren the polystyrene blocks have average molecilar weights between about 10,000 and 35,000 and the polybutadiene block has an average molecular weight between about 35,000 and 100,000 a mineral oil having a viscosity between about 45 and 100 SSU at 210 F. a liquid hydrocarbon boiling between about 105 C. and 150 C. hydrogenated rosin an alkylated dimethylphenol-formaldehyde resin having a molecular weight between about 350 and 1,500, a methylol content between about 10 and 16% by weight, and wherein the alkyl groups thereof have from 4 to 6 carbons each an alkaline earth metal carbonate having an average particle diameter between about 20 and 50 microns an alkaline earth metal carbonate having an averageparticle diameter between about 0.006 and 0.1

5. A composition according to claim 1 comprising:

Parts by weight v) a block copolymer having the configuration age molecular weight of the polybutadiene blocks being about 64,000 100 (b) a mineral oil having a viscosity of about 50-60 SSU at 210 F. 30-32 (c) toluene 100-105 (d) hydrogenated resin 135-145 (e) a butylated dimethylol phenol formaldehyde resin having a molecular weight between about 350 and 1,500 and a methylol content of 10 about 14%- by weight 25-35 (f) a calcium carbonate having an average particle diameter of 25-45 microns 190-215 (g) and a calcium carbonate having an average particle diameter between about 0.04 and 0.1 15 micron 225-265 References Cited UNITED STATES PATENTS 2,140,375 12/1938 Allen et al 23-66 2,198,223 4/1940 Muskat et a1. 23-66 2,708,192 5/1955 Joesting et a1. 117-122 2,963,387 12/1960 Herr et al. 260-846 3,239,478 3/1966 Harlan 26027 FOREIGN PATENTS 137,614 6/1950 Australia. 572,994 11/1945 Great Britain. 649,975 2/1951 Great Britain. 30 876,697 9/1961 Great Britain.

OTHER REFEREN CES Megson: Phenolic Resin Chemistry, 1958, pages 248- 250 relied upon.

DONALD E. CZAJA, Primary Examinen F. MCKELVEY, Assistant Examiner. 

1. A CALKING COMPOSITION FOR SEALING CREVICES, CRACKS, LEAKS, JOINTS AND THE LIKE TO MAKE THEM WATERPROOF COMPRISING AN INTIMATE MIXTURE OF: 